How to get entropy values of different images to a graph?

Hi,

I have calculated the entropy values of different images using the code I have shown below. Now I need to get the entropy values o several images to a graph. Can you please help me on that?

%read te image
I = imread('152.bmp');
subplot(2,2,1),imshow(I,map1)

I2 = imread('006.bmp');
subplot(2,2,3),imshow(I2,map2)

x = entropy(I);
x2 = entropy(I2);


[Height,Width] = size(I);



[m,Binsx] = imhist(I);

%normalize the counts
m = m/(Height*Width);

%get the sum of the histogram values
sprintf('the sum of the histogram value is = %g',sum(m));


subplot(2,2,2),plot(Binsx,m,'k')
xlabel('pixel value'),ylabel('relative count')

H = sum(-m.*log2(m));
sprintf('the entropy of the image is = %g',H)




%calculate height & width of the image
[Height,Width] = size(I2);



%get the histogram of the image in 256 bins
[n,Binsx] = imhist(I2);

%normalize the counts
n = n/(Height*Width);

%get the sum of the histogram values
sprintf('the sum of the histogram value is = %g',sum(n));

%
subplot(2,2,4),plot(Binsx,n,'k')
xlabel('pixel value'),ylabel('relative count')


H2 = sum(-n.*log2(n));
sprintf('the entropy of the image is = %g',H2)


%get the graph of the entropy values
figure(),plot(H,H2);

xlabel('image number'),ylabel('entropy value')

[Image Analyst]

Do you want both entropy values on one graph? Why not use bar() instead of plot()?

Answer 1

[KALYAN ACHARJYA]

I=imread('test.png');
I2=imread('test.jpg');
x=entropy(I);
x2=entropy(I2);
bar([x x2]);
set(gca,'xticklabel'); 
title('Entropy of Two Images');

Another Way:

I=imread('test.png');
I2=imread('test.jpg');
x=entropy(I);
x2=entropy(I2);
bar(1,x);
hold on;
bar(2, x2,'r');
bar_name={'Image 1' 'Image 2'};
legend(bar_name,'location','northwest');
title('Entropy of Two Images');

[Ishara Nipuni]

Thank you so much for the help. It will be very helpfull for me. :-) :-)

[KALYAN ACHARJYA]

Welcome @Ishara

I'm glad, it helped.

Good Wishes

Regards,

Kalyan Acharjya